According to my understanding and the error message, it seems there is an error in your MATLAB code. The error message suggests that you are using an invalid expression when trying to calculate r.
To fix the error, you need to use parentheses to indicate the function calls to sin and cos. Additionally, you have a typo in the variable name thetha, which should be corrected to theta.
Here's the corrected code:
theta = 0:pi/100:2*pi;
r = sin(theta).^2 + cos(theta).^2;
In this code, the sin and cos functions are called with the theta variable as the input. The (. ^) operator is used to perform element-wise squaring of the resulting values. Finally, the squared values of sin(theta) and cos(theta) are added together to calculate r.
Please note that r will be an array with the same size as theta, containing the calculated values for each angle.
I hope this helps! Let me know if you have any further questions.
Best Regards,
Simar